<!DOCTYPE html>
<html>
  <head>
    <script>
      function $(str) { return document.getElementById(str); }
      function hookLoad(str) {
        $(str).onload = function() { window.parent.loadEnded(); };
        window.parent.loadStarted();
      }
      window.onload = function() { 
      hookLoad("w");
        $("w").contentWindow.location.href = "passinner.png";
        hookLoad("x");
        var doc = $("x").contentDocument;
        doc.write('<img src="passinner.png">');
        doc.close();
      };
      function doIt() {
        hookLoad("y");
        $("y").contentWindow.location.href = "passouter.png";
        hookLoad("z");
        var doc = $("z").contentDocument;
        doc.write('<img src="passouter.png">');
        doc.close();
      }
    </script>
  </head>
  <body>
    <iframe name="w" id="w" width="100" height="100"></iframe>
    <iframe name="x" id="x" width="100" height="100"></iframe>
    <iframe name="y" id="y" width="100" height="100"></iframe>
    <iframe name="z" id="z" width="100" height="100"></iframe>
    <img src="passinner.png">
  </body>
</html>
